CHEMISTRY

ZLD Systems

Z.L.D. (ZERO LIQUID DISCHARGE) PILOT PLANT FOR THE TREATMENT, RECYCLE AND RECOVERY OF INDUSTRIAL WASTE WATERS.

This kind of plants has been developed in order to overcome the fresh water shortage that affects many industrial compounds, with the aim to reduce the fresh water consumption ( both surface and underground) and also to minimize the waste , mainly in areas where there are strong limitations to discharge process eluates.

SESPI has been continuosly committed in the research and development of this type of plants, and in particular takes part to a research program together with official partners specialized in this field.
Furthermore, a main scope of this research program, is to reduce the plant area, to simplify the operation and minimize both the investment and the operating costs, and ultimately, the unit cost of the recovered water.

The outline of the process to obtain a total wastes recovery, after several steps,is the following:

  •  Treatment Unit of the feed freshwater, for the power plant start-up 
  •  Oily waters treatment unit 
  •  Biologic wastes treatment unit 
  •  Neutralized waters treatment unit.

After the above mentioned treatments, using up to date and highly efficient processes, the several waters are fed to the water recovery unit,which consists of:

  • micro/ultra filtration pre-treatment unit 
  • R.O.section 
  • Demineralization with the electrodeionization process 
  • The concentrate discharged by the R.O unit is then processed by a low energy consumption cristallization unit.

The recovered water is then recycled both as process water and as boiler feedwater.

The advantages of this technology are mainly the near total water recovery, up to 90%, minimal plant area, reduced investment and operating costs, low energy demand, low impact on the ambient, and maximum dependability.